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Photo-oxidative Crack Propagation in Transition Metal Dichalcogenides

Authors :
Ben-Smith, Andrew
Choi, Soo Ho
Boandoh, Stephen
Lee, Byung Hoon
Vu, Duc Anh
Nguyen, Huong Thi Thanh
Adofo, Laud Anim
Jin, Jeong Won
Kim, Soo Min
Lee, Young Hee
Kim, Ki Kang
Source :
ACS Nano; January 2024, Vol. 18 Issue: 4 p3125-3133, 9p
Publication Year :
2024

Abstract

Monolayered transition-metal dichalcogenides (TMDs) are easily exposed to air, and their crystal quality can often be degraded via oxidation, leading to poor electronic and optical device performance. The degradation becomes more severe in the presence of defects, grain boundaries, and residues. Here, we report crack propagation in pristine TMD monolayers grown by chemical vapor deposition under ambient conditions and light illumination. Under a high relative humidity (RH) of ∼60% and white light illumination, the cracks appear randomly. Photo-oxidative cracks gradually propagated along the grain boundaries of the TMD monolayers. In contrast, under low RH conditions of ∼2%, cracks were scarcely observed. Crack propagation is predominantly attributed to the accumulation of water underneath the TMD monolayers, which is preferentially absorbed by hygroscopic alkali metal-based precursor residues. Crack propagation is further accelerated by the cyclic process of photo-oxidation in a basic medium, leading to localized tensile strain. We also found that such crack propagation is prevented after the removal of alkali metals via the transfer of the sample to other substrates.

Details

Language :
English
ISSN :
19360851 and 1936086X
Volume :
18
Issue :
4
Database :
Supplemental Index
Journal :
ACS Nano
Publication Type :
Periodical
Accession number :
ejs65188334
Full Text :
https://doi.org/10.1021/acsnano.3c08755